Update mini changelog

docs/_includes/changelog.html

@@ -1,6 +1,7 @@
 <h2>Changelog<a href="#changelog"></a></h2>
 <p>For a more detailed changelog, visit <a href="https://github.com/Vestride/Shuffle/releases">the latest releases</a> on GitHub.</p>
 <ul>
+  <li><code>v5.1.0</code> 2/20/18 - Add <code>compare</code> option to sorter. Add <code>es</code> build to package and <code>"module"</code> field to <code>package.json</code>.</li>
   <li><code>v5.0.3</code> 10/30/17 - Fix rounding error.</li>
   <li><code>v5.0.2</code> 9/23/17 - Update type definitions. Upgrade dev dependencies.</li>
   <li><code>v5.0.1</code> 7/18/17 - Add <code>roundTransforms</code> option.</li>